The invention relates to a functional feeder unit of a low-voltage electrical cubicle containing:
a vertical multipole busbar comprising conducting bars extending edgewise in parallel vertical planes staggered along the transverse direction between two flanges, PA1 a mounting plate for support and connection of an electrical apparatus, PA1 a protection grid positioned at the front of the bars, said grid being equipped with holes, PA1 and means for electrical connection of the mounting plate to the busbar comprising a connection interface with draw-in contacts, inserted between the protection grid and the mounting plate, each contact passing through a predetermined hole of the grid to engage on the bar of the corresponding phase. PA1 the mounting plate comprises coplanar current conductors presenting different lengths, with a heightwise offset in the extension direction of the bars, PA1 the draw-in contacts are arranged obliquely on a plate of the connection interface, with an offset corresponding to the distance between the bars of the different phases, PA1 and centering means perform positioning of the plate on the protection grid to align the ends of the current conductors of the mounting plate on the bars in a direction perpendicular to the connection interface.
The connecting means currently used are formed either by connecting cables or by fixing brackets requiring connection operations by clamping. In the first case, the ends of the cables comprise spade connectors fixed onto the bars by means of assembly screws. In the second case, the fixing brackets are secured to the branch conductors of the mounting plate and the assembly is secured directly to the busbar. Such an installation is fixed and does not enable upgrading towards disconnectable or withdrawable solutions. A maintenance operation on the installation requires the busbar to be powered off, which is detrimental to continuity of service.
The document FR-A-2,562,344 describes a low-voltage distribution installation comprising a vertical multipole busbar and a metallic protection grid provided with holes and positioned at the front of the bars. A connection interface with draw-in contacts is inserted between the protection grid and the mounting plate supporting the electrical apparatuses, each contact passing through a predetermined hole of the grid to clamp onto the corresponding phase bar. The first series of draw-in contacts is arranged in a single horizontal plane on one face of the connection interface. A second series of female contacts is necessary on the opposite face of the connection interface to perform connection of the electrical apparatuses to the busbar. The depthwise dimensions of such a connection interface are very large and assembly of the installation takes longer due to the large number of connection parts.